Sign considering modal combination methode

[OLK]

All the widely known modal combination methods (SRSS, CQC, ABS, 10% etc) disregard the sign of the modal responses.

Is there any combination method, taking in account the sign of the modal responses?
Or, any combination method that gives pseudo time-related results?

 

[Akeee]

Hello, i dont know about the last question, but what i do to verify if i got it right, i am using a secound series of loading combination with seismic shear coffienct, i try to calibrate with the spectral one and i have a unit of measure.